1. Field of the Invention
The present invention relates to an apparatus and method for coating a film such as an interlayer dielectric film on a substrate such as a semiconductor wafer.
2. Description of the Related Art
In the manufacturing process of a semiconductor device, a dielectric film such as an interlayer dielectric film is spin-coated on a semiconductor wafer by, for example, the sol-gel method, the silk method, the speed film method or the Fox method, and is applied a chemical treatment, or a heat treatment so as to form a desired film. For example, in the silk method, speed film method and Fox method, a spin-coat solution is coated on a cooled semiconductor wafer, then heated and cooled. Further, in a low oxygen concentration atmosphere the wafer is heated and then cooled so as to cure the coated film.
If the oxygen concentration is raised during heating the wafer in the curing process, a dielectric constant of the interlayer dielectric film becomes high. Therefore, a prescribed amount of an inert gas such as a nitrogen gas is introduced during heating in the curing process the wafer placed in a chamber. Concretely, a plurality of gas nozzles are employed around a circumference of the wafer placed on a hot plate in the chamber in order to introduce the inert gas and the gas inside the chamber is exhausted from an exhaust port over the center of the hot plate.
However, the inert gas flows in different manners depending upon the location of the wafer which is near to or distant from the nozzles which are disposed at fixed positions. Therefore, The temperature on the wafer is made uneven and the oxygen concentration around the wafer is made uneven, thereby reducing uniformities of film characters such as a dielectric constant, hardness and peel strength.
An object of the present invention is to provide a heat treatment apparatus and method which are capable of heating uniformly over the entire surface of a substrate such as a semiconductor wafer, by supplying uniformly the substrate with a prescribed gas.
The heat treatment apparatus of the present invention comprises: a hot plate on which the substrate is placed; a chamber for containing the hot plate; a gas supply mechanism for supplying the chamber with a prescribed gas; a baffle member which surrounds the substrate in the chamber and is provided with a plurality of gas blowing apertures for supplying the prescribed gas from the gas supply mechanism; and a rotation mechanism for rotating or turning round the baffle member.
Further, the heat treatment apparatus of the present invention may comprises: a hot plate on which said substrate is placed; a chamber for containing the hot plate; a gas supply mechanism with a plurality of gas exits for supplying the chamber with a prescribed gas; and a rotation mechanism for rotating or turning round the gas exits.
Further, the heat treatment apparatus of the present invention may comprises: a hot plate on which the substrate is placed; a chamber for containing the hot plate; a gas supply mechanism for supplying the chamber with a prescribed gas; and a gas diffusion mechanism for diffusing the prescribed gas from the gas supply mechanism which includes: a baffle member which surrounds the substrate in the chamber and is provided with a plurality of gas blowing apertures for supplying the prescribed gas from the gas supply mechanism; a plurality of fins which is provided at the baffle member and rotates by a pressure of the prescribed gas from the gas supply mechanism; and a baffle member support means for holding the baffle member.
Further, the heat treatment method of the present invention comprises the steps of: a first step for placing the substrate on a hot plate; a second step for arranging a baffle member thereby surrounding the hot plate; and a third step for supplying the substrate with an inert gas from a plurality of gas blowing apertures provided at the baffle member which is rotated or turned round thereby moving said plurality of gas blowing apertures.
Further, the heat treatment method of the present invention may comprises the steps of: a first step for placing the substrate on a hot plate: a second step for containing the hot plate in a chamber: a third step for heating the substrate, by supplying the substrate with a prescribed inert gas from a plurality of moving gas exits which are rotated or turned round around the substrate, and at the same time by exhausting the chamber.
Further, the heat treatment method of the present invention may comprises the steps of: a first step for placing the substrate on a hot plate; a second step for containing in a chamber the hot plate and a baffle member which surrounds the substrate; a third step for heating the substrate, by supplying the substrate with a prescribed inert gas from a plurality of moving gas blowing apertures which are rotated or turned round around the substrate by using a pressure of the prescribed inert gas to fins provided at the baffle member, and at the same time by exhausting the chamber.
According to the present invention, an inert gas during the heat treatment is applied uniformly all over the surface of the substrate, by using moving gas blowing apertures or moving gas exits, thereby accomplishing a uniform heat treatment of the substrate, obtaining uniform and high quality films on the substrates, reducing inferior and defective products and improving a product yield.